Conventionally, a private farmer and a farming group manage an agricultural field, an agricultural operation, an operator (an agricultural operator) for the agricultural operation, and the like. These agricultural managements are usually carried out by using a notebook and the like; however, the agricultural managements increasingly depend on the IT in accordance with development of the information technology. Patent document 1 discloses a data collection system as a technique for carrying out the agricultural managements by using a computer and the like. In addition, Patent document 2 discloses a data communication system as a technique for obtaining information of a working machine.
The data collection system disclosed in Patent document 1 includes: a management terminal having a data recording means and a data display means; and a control device of an agricultural machine, the control device being connected to the management terminal to be capable of communicating with each other. The data collection system is configured to be characterized by sending a conversion factor of sensor information determined for each of the agricultural machines in sending the sensor information from the control device to the management terminal, the sensor information being detected by a sensor of the agricultural machine.
The data communication system disclosed in Patent document 2 is a communication system including: a first controller configured to output control data to a data bus for the CAN communication, the control data being used for controlling a working machine; a second controller configured to control the working machine separately from the first controller; and a third controller configured to be connected to the data bus for the CAN communication. The data communication system is a system configured to intermittently send operation information to the data bus when the data bus shows a free communication state, and to take the operation information by using the third controller.